A gym charges $5/hour for the first four hours of use in a week, and a total flat rate of $20 after that. a) How much would you spend going to the gym for three hours in a week? 5? 10? b) When is it a better value to go more hours? c) What would be the piecewise function that models the total cost of the gym in a week according to the number of hours spent there? d) What would be the piecewise function that models the cost/hour of the gym according to the number of hours spent there?